Baskets, of course, were the cheapest universal carrying container. We still use the standard English basket size that emerged from medieval measuring: the bushel.
Bushels started as the typical size that a merchant could load onto a pack mule. During most of the Middle Ages, Europe’s roads were barely good enough for wheeled vehicles to travel on. Two-wheeled carts could negotiate bad roads more easily than four-wheeled wagons. Horses and mules with packs could navigate any kind of road, including a track going through the hills. So while two-wheeled carts carried most goods in town, pack animals carried most goods out into the countryside and sometimes from town to town.
So the bushel didn’t start out as defined by so many pints, pecks, or pounds. It started out as a bushel: the right size to properly load on a mule’s pannier harness. Of course, merchants who purchased by the bushel wanted to standardize the size. During the medieval period, it was divided into gallons and pints. Each town had its standard bushel, probably made from copper or brass instead of basketweaving. As with other measures, by the end of the period, the king’s office of weights and measures had owned a royal bushel by which the legal volume was determined. When bushels of grain were measured out in the Port of London, the measuring team had leveling rods to make sure each bushel was exactly right, no more. (Merchants carried away the measured goods in their own basket-bushels.)
Four pecks were in a bushel, and so were eight gallons. These, too, had official volume measures in town. Eight bushels, together, made a “quarter,” though I’m not sure what the volume was a quarter of. It probably referred to the size of the two-wheeled cart used to move it around in town. One of the items sold by the quarter was charcoal.
Carts and wagons had standard sizes too, since they could be containers. It’s possible that “quarter” referred to the cart being one-quarter the size of a standard wagon. Wagons always required teams of oxen or horses to pull them. They were used to move the king’s furniture from manor to manor (some kings traveled almost constantly), and they were used for very large loads, like hay. Two-wheeled carts, on the other hand, could be pulled by a laborer or a single animal. Towns were filled with constant cart traffic as nearly every raw material was delivered this way.
I want to touch on measurement by length, although it’s off the subject of containers. The two important length measurements were for land and for cloth. Land was traditionally measured by how much a man with an ox could plow in one day. This measure, the acre, was divided into furlongs, which were envisioned as the strip that the plow made before it had to turn around and go back. It was something less than 1/8 of a modern mile, and the acre was defined as one furlong long, by 4 rods wide—the rod being 1/40th of a furlong. Square acres made no sense to medieval plowmen, since it was much more convenient to turn the ox and plow as seldom as possible.
Cloth measurement was highly local and regional, but since the highest volume of cloth was sold in the international fairs of Champagne, the Champagne measurements gradually became dominant. Even so, the measurements were very different from place to place. In Troyes, a bolt of cloth was 28 ells (the ell was roughly our yard, but it varied a lot). In Ypres, the bolt was only legal if it measured 29 ells. At Provins, they didn’t sell it by bolts at all, but by cords and lengths. A cord was 12 ells, and a length was 12 cords (144 ells).
The Champagne fairs also standardized the foot, since some materials were sold in much shorter lengths. Each fair had an official iron ruler with feet and inches–and the inches were also split into 12, each one called a line. Merchants at the fair were required to have wooden rulers that precisely matched the fair’s standard. (Every fair had its own justice system, too.) When sovereignty over Champagne came to the French crown, the king over-taxed the fairs and killed them entirely. They never got to work out a truly standard measurement of length.